The effect of high energy milling on the solid state synthesis of MnFe2O4 from mixtures of MnO-Fe2O3 and Mn3O4-Fe2O3

A thermal treatment at 900 °C (under nitrogen) of a milled mixture MnO-Fe2O3 yields MnFe2O4 mainly as the product of the reaction between Mn3O4 (produced by ball milling) and Fe2O3. Under the same experimental conditions but starting from an unmilled MnO- Fe2O3 mixture, the formation of MnFe2O4 is only partial and occurs through Mn3O4 (formed by oxidation of MnO). The same thermal treatment (900 °C under nitrogen) of a milled Mn3O4-Fe2O3 mixture yields MnFe2O4 mainly as the product of the reaction between Mn3O4 and Mn2O3/MnO2 (the higher Mn oxides being produced by ball milling) and Fe2O3. The effect of high energy milling is more pronounced in the case of the Mn3O4-Fe2O3 system since no MnFe2O4 formation is observed when starting from a physical mixture.